Craig Saper (2006), before I fully understood what blogging was. I started blogging myself at the end of 2008, particularly my Critical psychiatry blog. Jolly et al (2016) reflect on 'blogademia' in a recent article in The Psychologist.
I've commented before on why I blog (Writing down thoughts on your mind for everyone to see and Blog resistance). Blogs are publicly available. There's no reliance on finding a publisher. Social media in general is user-generated, deinstitutionalised, interactive communication, which makes some academics wary of these publications as they are outside peer-reviewed journals.
Blogs do need to be of sufficient quality to merit publication. They can help maintain academic freedom in a university system motivated by commercial interests.